Responses
1-He says in the beginning he was in love with his brother's wife but then he left because he wanted to put an end to his feelings.
2- Ml said to him " It's okay to do it (have sex) with Noonim but not me ? I know it all"
3- When his brother said "look your nephew grew up" his reaction was very sus
Idk honestly I thought I had a theory but I read the beginning again again and thought maybe it was obvious

So short But hey I have a theory ! You know when they met again and ml was like " Noonim is okay but not me ? I know it all" and the way he reacted to the all "look it's your nephew" thing...I think maybe ...